During infrastructure construction, a gap is intentionally provided between adjacent structural members for accommodating dimensional changes within the infrastructure. Such dimensional changes occur as a result of expansion and contraction of the structural members due to conditions including, but not limited to, temperature changes, shortening caused by pre- and/or post-stressing of the concrete sections, creep, seismic disturbances, as well as deflections and longitudinal forces caused by vehicular traffic.
An expansion joint system is typically utilized to accommodate such gaps within infrastructure construction including movements in the vicinity of such gaps. An expansion joint is typically formed by sealing the gap between adjoining structural members with an expansion joint and applying a mass of structural material (a.k.a., a header material) to each side of the joint opening. Expansion joint systems are capable of accommodating dimensional changes to the gap occurring with the expansion and contraction of the structural members due to factors listed above.
Expansion joint systems, particularly in heavily trafficked bridge structures, sports stadiums, parking garages and airports are degraded when the header material must bear the wear and tear caused by contact with vehicle wheels. The expansion joint material can be compromised from the gap between the structures when the adhesion between the concrete material and the expansion material degrades allowing the ingress of water and development of damaging affects.
In addition, header compositions typically have a short working time (also referred to as pot life) before cure. At higher temperatures, the working time is even shorter as higher temperatures generally result in shorter working times. This poses a problem because such header compositions do not provide for an adequate amount of time for the header material to be applied properly within an expansion joint system.
Therefore, a need exists in the art for an improved expansion joint system and header material which is capable of resisting degradation by providing improved performance and which provides for an adequate amount of time to be applied before cure.